85 entries under hard topic. ×

2
insensible(adjective, strong, tough, inflexible)
2
rigorous(resolute, rigid, inflexible, strict)
2
solid(adjective, set, strong, tough)
2
thick(adjective, strong, tough, firm)
2
unchangeable(adjective, set, stiff, rigid)
1
bullhead(adjective, mean, tough, harsh)
1
callous(adjective, set, mean, strong)
1
coke(noun, metal, pretzel)
1
cold fish(expression, adjective, mean, unfeeling)
1
fixed(adjective, mean, strong, tough)
1
hanging tough(expression, adjective, mean, rigid)
1
hard-and-fast(adjective, set, stiff, rigid)
1
hard-boiled(adjective, mean, tough, harsh)
1
hard-hearted(adjective, mean, tough, harsh)
1
hard-nosed(adjective, mean, tough, harsh)
1
mean(adjective, tough, harsh, unfeeling)
1
mulish(adjective, mean, strong, tough)
1
perverse(adjective, mean, tough, firm)
1
pigheaded(adjective, mean, tough, firm)
1
set in stone(expression, adjective, idiom, mean)
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APASmart Define. (2015). iron thesaurus. Retrieved September 28, 2026, from https://smartdefine.org/iron/thesaurus/synonyms
ChicagoSmart Define. 2015. "iron thesaurus" https://smartdefine.org/iron/thesaurus/synonyms (accessed September 28, 2026).
HarvardSmart Define 2015, iron thesaurus, Smart Define, viewed 28 September, 2026, <https://smartdefine.org/iron/thesaurus/synonyms>.
MLASmart Define. "iron thesaurus" 14 April 2015. Web. 28 September 2026. <https://smartdefine.org/iron/thesaurus/synonyms>